One benefit might be turning a semiarid and, in some places, arid region
into a more temperate one. This might allow even more food to produce in
that area. Another might be allowing waterborne travel and trade to become
practical in the region.

Now i'm discussing this idea here to see where it can go. I'm not sure I'd
actually be committed to doing this, since so it has too many unknown
consequences, many of which might be detrimental to human and nonhuman life.